The Westinghouse Corporation, the Swedish National Development Corporation and others avidly pursued the development of the iron-air battery during the mid-1970s and early 1980s for use in electric vehicles. However, the energy density and power density of these batteries did not reach the desired targets set for electric vehicle applications.
Advantages for potential use of the iron-air battery in grid-scale energy storage applications are compelling. An iron-air battery is less expensive than other batteries, with iron only costing $0.10 per pound. The United States has over 100 billion tons of iron ore resources, which translate to over 10,000 teraWh of energy storage. Iron is non-toxic and easily recyclable. The iron-air battery has a high energy density, with a theoretical specific energy of 764 Wh/kg. Even at 20% of this value (154 Wh/kg), it is comparable to the specific energy of Li-Ion batteries. The iron electrode is robust, with over 3000 cycles demonstrated with the iron electrode in nickel-iron batteries. Furthermore, the iron electrode is very tolerant to overcharge, over-discharge, and open circuit stand.
Current iron-air batteries have a moderate energy density (50-75 Wh/kg), moderate cycle life (2000 cycles), are low cost (<$100/kWh), are environmentally friendly, are constructed from abundant raw materials, and are easily scalable. However, the round-trip energy efficiency and cycle life of the iron-air battery require improvement.